Alpha-Conotoxin GI

**Semantic type:** Hazardous or Poisonous Substance

**Definition:** A 13-amino acid alpha-conotoxin that is isolated from the venom of the cone snail Conus geographus. It is a competitive antagonist of the muscle-type nicotinic acetylcholine receptors, blocking synaptic transmission at the neuromuscular junction. Alpha-conotoxins are identified by a characteristic arrangement of four-cysteine residues (-CC-C-C-) and disulfide bonding of Cys1-Cys3 and Cys2-Cys4.

**Synonyms:** - ALPHA-CONOTOXIN GI - Alpha-GI - Alpha-GI